In modern-day injection systems for internal combustion engines, piezoelectric actuators are employed as actuating elements for injection valves. In order to protect the piezo actuators against damaging environmental influences the actuators are provided with sealed housings. In this case the electric supply lines of the actuator must be fed through the housing enclosing the actuator.
DE 197 15 487 A1 discloses a piezo actuator which consists of a prefabricated hollow profile into which the piezo elements and two contact pins which serve for electrically contacting the piezo elements are introduced. A cover is mounted onto the hollow profile containing the inserted piezo elements and the inserted contact pins and is subsequently injection-molded with plastic.
A disadvantage with the described structure is for example that it is necessary to avoid the injection molding compound penetrating into the interior of the actuator. Moreover, injection molding with plastic is complicated, costly and time-consuming. In addition, the sealing action of the plastic at the feed-throughs for the connecting contacts is also unsatisfactory, with the result that the interior of the actuator is inadequately protected against penetrating engine oil or penetrating water.